We had an Amana ASZC18 Heat Pump installed and the backup heat will be provided by a Thermo Pride OH6 2 Stage Oil Furnace with an Aprilaire 400 whole house humidifier. The tech that wired the system to the Prestige IAQ thermostat didn't seem to know what he was doing (confirmed by the wiring to the humidifier). The short version is he has the cable from the heat pump going to the furnace board where it is rigged to another cable that goes from the furnace board up to the EIM. There is another cable which is also connected to the other two cables which goes to the Humidistat for the humidifier. I discovered he had the humidifier solenoid wired completely wrong. Yes it is a very messy looking piece of work!
My impression was that the Heat Pump cable, the furnace board cable and the humidifier would all go directly to the EIM and be controlled by the IAQ. The reason for getting this thermostat was because I was told the system needed a stat with 4 stages of heat and 2 stages of cool. Now I'm not sure if it is wired or working correctly. Any thoughts or can anyone do a diagram on the correct wiring for this system?